% !TeX program = xelatex
% !TeX encoding = UTF-8
\documentclass[UTF8]{standalone}
\usepackage{amsmath,newtxmath,ctex,tikz,siunitx}
\setCJKmainfont{SourceHanSerifCN}%
[
	UprightFont = *-Regular,
	BoldFont = *-Bold,
	ItalicFont = 方正新楷体简体,
	BoldItalicFont = *-Bold,
	Mapping = fullwidth-stop
]
\usepackage{newtxtext}
\begin{document}
\begin{tikzpicture}
	\draw[domain=-2:2,smooth,samples=500]  plot[id=1] function{(1-x**2/4)**0.5};
	\draw[domain=-2:2,smooth,samples=500]  plot[id=2] function{-(1-x**2/4)**0.5};
	\draw[-latex] (-2.5,0) -- (3.91421356,0) node[below] {$x$};
	\draw[-latex] (0,-1.5) -- (0,3) node[left] {$y$};
	\node[below=5pt,left=-3pt] at (0,0) {$O$};
	\node[right=3pt,below] at (2,0) {$2$};
	\node[left=5pt,above] at (0,1) {$1$};
	\draw (2,0) -- ++ (45:2);
	\draw[domain=-0.385786437:3.41421356,smooth,samples=500]  plot[id=3] function{(1-(x-1.41421356)**2/4)**0.5+1.41421356};
	\draw[dashed] (1.8,{(1-1.8^2/4)^0.5}) -- ++ (45:2) -- ++ (-3.6,0);
	\draw (2,0) ++ (45:2) -- ++ (1,0);
	\draw[latex-latex] (2.7,0) -- node[right] {\SI{4}{m}} ++ (45:2);
	\draw[dashed] (1.8,{(1-1.8^2/4)^0.5}) -- (-1.8,{(1-1.8^2/4)^0.5});
	\draw (-1.8,{(1-1.8^2/4)^0.5}) -- ++ (45:2);
	\draw (0.4,1.3) -- ++ (0,0.2);
	\draw (0.8,1.3) -- ++ (0,0.2);
	\draw (0.6,1.5) ellipse (0.2 and 0.1);
	\draw (0.4,1.5) -- ++ (160:1.5) -- ++ (-1.2,0) node[above=5pt,right=-2pt] {抽水口};
	\draw[dashed] (-1.8,0.25) -- (1.8,0.25);
	\draw[dashed] (-1.8,0.15) -- (1.8,0.15);
	\draw[dashed] (-1.2,-0.6) -- (1.2,-0.6);
	\draw[dashed] (-0.5,-0.8) -- (0.5,-0.8);
	\draw[dashed] (-1.7,-0.2) -- (-0.4,-0.2);
	\draw[dashed] (-1.7,-0.4) -- (1.7,-0.4);
	\draw[dashed] (1.7,-0.2) -- (0.4,-0.2);
\end{tikzpicture}
\end{document}
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